JPS60160272A - Superimposer - Google Patents

Abstract

PURPOSE:To attain video-recording of a computer picture and a superimposed video signal between the said picture and a picture of video medium on a VTR by inputting a synchronizing signal of a video signal and a synchronizing signal from a computer and providing a clock to the computer so that each synchronism is coincident. CONSTITUTION:The input video signal is separated into a synchronizing signal and a blanking signal B by a synchronism separating circuit 15, demodulated into a subcarrier signal SC and a chrominance signal by a color demodulation circuit 14 and a pattern synchronism circuit 17 makes each said synchronizing signal coincident with each synchronizing signal from the computer PC. Then in selecting the PC picture mode by a mode selection circuit 24, a switch control circuit 23 switches an analog switch 16 and a PC video signal in synchronizing with the external video signal is outputted from a video signal output terminal 11. In selecting the superimposing mode, the control circuit 23 switches the switch 16 to the other position and the superimposed picture signal between the video signal from the external part and the video signal from the PC is outputted from an output terminal 11.

Description

DETAILED DESCRIPTION OF THE INVENTION [Technical Field of the Invention] The present invention relates to a superimposer that superimposes a video signal input from a home video tape recorder or the like and a video signal input from a computer.

[Technical background of the invention and its problems] For example, there is a strong need to directly record computer images on a home video tape recorder (hereinafter referred to as a VTR). However, since most computer video signals are not based on the NTS'C system, there are problems in that the screen cannot be recorded clearly, such as the screen being distorted. Furthermore, conventionally, there has been a problem in that image information from video media such as video discs and video cameras cannot be easily superimposed on a computer screen.

- [Purpose of the Invention] This invention has been made to solve the above problem, and it is possible to easily perform VTR recording of a computer image and a video signal in which a computer image and a video media image are superimposed. The purpose is to provide a superimposer that can.

Another object of the present invention is to provide a superimposer that can inhibit the output of an input audio signal when outputting a computer image.

Furthermore, the present invention can externally adjust the brightness of the computer image, providing better VT of the computer image.
The purpose of this invention is to provide a superimposer that can perform R recording.

[Summary of the Invention] This invention provides a synchronization separation circuit that inputs a video signal and separates a vertical synchronization signal and a horizontal synchronization signal, and a demodulation circuit that inputs the video signal and demodulates a subcarrier signal and an image signal. , the vertical and horizontal synchronization signals of the video signal obtained from the synchronization separation circuit are input, and the vertical and horizontal synchronization signals are also input from the computer.
a screen synchronization circuit for supplying a clock to the computer so that horizontal synchronization is consistent; a switching means for selectively outputting an image signal obtained from the demodulation circuit and an image signal obtained from the computer; a modulation circuit that receives an output image signal, vertical and horizontal synchronization signals obtained from the synchronization separation circuit, and subcarrier signals obtained from the demodulation circuit, and outputs a video signal and a radio frequency signal, and the computer; controlled by
The superimposer includes a switching means control circuit that controls the switching means.

Further, the present invention is provided with a prohibition circuit that prohibits the output of the input audio signal when only the image signal from the computer is selected by the switching means.

Furthermore, the present invention is provided with a degree adjustment means for externally adjusting the brightness of the image signal from the computer.

[Embodiments of the invention] Embodiments of the present invention will be described below with reference to the drawings.

FIG. 1 is a perspective view showing the external appearance, and 1 is a case. On the top of the case 1 are a video mode selection button 2, a superimpose selection button 3, a computer mode selection button 4. are provided for each. Also, the case 1
A fuse compartment 5 and a power indicator lamp 6 are provided on the front side, and an input terminal 7 for inputting a color video signal from a computer, an audio signal input terminal 8, and a terminal for inputting a color video signal from a computer, an audio signal input terminal 8, a home VTR, a video disc, a video camera, etc. an input terminal 9 for inputting a color video signal from a video camera;
An output terminal 10 for outputting an audio signal and an output terminal 11 for outputting a video signal are provided. Note that 12 is a power cord.

FIG. 2 is a block diagram showing a circuit configuration built into the case 1, in which a video signal inputted from the video signal input terminal 9 is passed through a buffer circuit 13 to a color demodulation circuit 14.
and is supplied to the synchronous separation circuit 15. As shown in FIG. 3, the buffer circuit 13 is a well-known circuit composed of a transistor, a resistor, a capacitor, and a diode. The color demodulation circuit 14 is provided with a color demodulation control IC 141 as shown in FIG. 3, receives the horizontal synchronization signals VD and H-8YNC from the synchronization separation circuit 15, and converts the input video signal into a subcarrier signal. SC, red, green,
It is demodulated into blue color signals R, G, and B. The synchronous separation circuit 15 is made up of a plurality of transistors, comparators, flip-flops, resistors, capacitors, etc., as shown in FIG. 5 by a partial circuit 15A and FIG. 4 by a remaining partial circuit 15B. vertical synchronization signal VD,
V-8YNC,, horizontal synchronization signal VD, H-8YNC,,
The blanking signal BLANK is separated and outputted. Each color signal G, R, B from the color demodulation circuit 14
is outputted to the video signal output terminal 11 through one contact of an analog switch 16 serving as a switching means.

The analog switch 16 is composed of three elements 161, 162, and 163 as shown in FIG.

Sync signal VD from the sync separation circuit 15, H-3YN
C,, VD, and V-8YNC are supplied to the screen synchronization circuit 17 and the modulation circuit 18. As shown in FIG. 4, the screen synchronization circuit 17 includes a plurality of D-type flips 7O tabs 171.
17'2.173.174, phase-frequency conversion circuit 17
5. A clock generation circuit 176 is provided, and the synchronization separation circuit 15tfi (7) Ii51 M signal j) VD, H
In addition to V-8YNC, VD, and V-8YNC, a vertical synchronizing signal PC, V-8YNC, and horizontal synchronizing signal PC, l-1-8YNC are input from the computer PC to generate a synchronizing signal VD.

Synchronous signal spc to H-8YNC, VD, V-8YNC,
,V-8YNC,,PC,H-syNc.

The clock signal CLOCK is supplied to the computer PC so that the clock signals coincide with each other. The computer PC also includes one brightness modulation circuit, Green Glud R,
It supplies blue B color signals. The brightness modulation circuit 19 includes a brightness modulation control IC 191 as shown in FIG.
, a gate circuit 192, which inputs the blanking signal BLANK from the synchronization separation circuit 15, modulates the brightness of each color signal from the computer PC, and changes the level of the brightness modulation to a digital brightness signal comprising, for example, a microswitch circuit. The adjustment circuit 20 allows it to be changed externally. The brightness modulation circuit 19 outputs each color signal of green G, red R1 and blue B after brightness modulation to the video signal output terminal 11 via the other contact of the analog switch 16. The color demodulation circuit 1 obtained through the analog switch 16
4 or each color signal G, R from the brightness modulation circuit 19.

B is also supplied to the modulation circuit 18. The audio signal input from the audio signal input terminal 8 is output to the audio signal output terminal 10 via one contact of the analog switch 21, and the modulation circuit 1
8. The modulation circuit 18 receives each color signal G, R.
, B are modulated into video signals and output, and the video signals and audio signals are further combined to output high frequency TV signals (R, F signals).

Each color signal G, R from the computer PC.

B to the analog switch 16 via the gate circuit 22.
．． 21 is supplied to a switch control circuit 23 that controls the switch control circuit 21. This switch control circuit 23 also includes a mode selection circuit 2.
A mode selection signal is input from 4.

When either of the color signals G1R and B from the computer PC is valid, the switch control circuit 23 forcibly switches the analog switch 16 to the other contact, and also selects the computer image mode from the mode selection circuit 24. The signal PCON, the superimpose mode signal IMON, and the external image mode signal VDON cause the analog switch 16 to select the image signal from the computer PC or superimpose the computer image signal and the external image signal. , which controls which external image signal is selected. Further, the switch control circuit 23 forcibly switches the analog switch 21 to the other contact when performing control to select the image signal of the computer PC. The mode selection circuit 24 includes flip-flops 241.242.243.244.245.2 as partially shown in FIG.
46, etc., and the computer image mode signal PCON described above with computer image, superimpose, and external image designation signals PC8, IMS, and VDS.

The superimpose mode signal IMON and external image mode signal VDON are selectively output.

In the apparatus according to the embodiment of the present invention configured as described above, the video signal input from the outside is processed by the synchronization separation circuit 15 into vertical synchronization signals VD, H-3YNC and horizontal synchronization signals VD, V-3.
The signal is separated into YNC and a blanking signal BLANK, and demodulated by the color demodulation circuit 14 into a subcarrier signal @SC and each color signal of green, red, and blue. Then, the screen synchronization circuit 17 receives each synchronization signal VD from the synchronization separation circuit 15.
.

H-8YNC1VD, H-3YNC and computer PC
Each synchronization signal from PC, H-8YNC, PC, V-8Y
Consistency with NC is achieved. Therefore, the mode selection circuit 2
When the computer image mode is selected in step 4, the switch control circuit 23 switches the analog switch 16 to the other contact side, and the video signal of the computer PC synchronized with the external video signal is output from the video signal output terminal 11, allowing the computer image to be displayed at home. It becomes possible to record directly onto video media such as VTRs and video discs.

Furthermore, when the mode selection circuit 24 selects the superimpose mode, the switch control circuit 23 switches the analog switch 16 to the other contact side when each color signal G, R, B from the computer PC is valid, and the video signal An image signal obtained by superimposing an external video signal and a video signal from the computer PC is output from the output terminal 11. However, household V
An image obtained by superimposing images such as characters and figures from a computer PC onto an image from a TR can be directly recorded on a home VTR. Moreover, since the image synchronization signal from the computer is synchronized with the image synchronization signal from the home VTR input externally, problems such as screen drifting do not occur when playing superimposed video signals. Always get clear images.

Furthermore, since the brightness of the image from the computer PC can be varied externally by the brightness modulation circuit 19 and the brightness adjustment circuit 20, the brightness of the image from the computer can be adjusted in accordance with the video signal from the outside, making it possible to Superimposed images can be obtained, making it a better VTR.
Can record. Roughly speaking, in this case, since the output of audio signals is prohibited when each color signal from the computer is selected, there is no risk that the audio signals recorded on the external VTR will be adversely affected by superimposition. .

Further, when the external image mode is selected by the mode selection circuit 24, the switch control circuit 23 switches the analog switch 16 to one contact side, so that the video signal from the outside is outputted from the video signal output terminal 11 as it is. become. In this case, recording from a home-use VTR to a home-use VTR becomes possible.

In this way, an image from a computer PC or an image obtained by superimposing an image from a computer PC and an image from an external VTR can be easily and clearly recorded on a home VTR. In addition, there is no possibility that the audio signal from the external TR will be adversely affected during superimposition, and excellent superimposition processing can be performed.

In the above embodiment, the case of a color video signal has been described, but the invention is not necessarily limited to this, and the same effect can be obtained even in the case of a black and white video signal.

[Effects of the Invention] As detailed above, the present invention provides a superimposer that can easily perform VTR recording of a computer image and a video signal in which a computer image and a flea image on video media are superimposed. It is possible to provide

Further, according to the present invention, it is possible to provide a superimposer that can prohibit the output of an externally input audio signal when outputting a computer image.

Further, according to the present invention, it is possible to provide a superimposer that allows external adjustment of the brightness of computer images and enables better VTR recording of computer images.

[Brief explanation of the drawing]

The figures show an embodiment of the present invention, in which Fig. 1 is a perspective view showing the external appearance, Fig. 2 is a block diagram showing the circuit configuration, and Fig. 3 shows the buffer circuit, color demodulation circuit, and analog switch in Fig. 2. FIG. 4 is a specific circuit diagram of a part of the screen synchronization circuit and sync separation circuit in FIG. 2, and FIG. 5 is a specific circuit diagram of a part of the brightness modulation circuit and sync separation circuit in FIG. 2. , FIG. 6 is a specific circuit diagram of a part of the mode selection circuit in FIG. 2. 14... Color demodulation circuit, 15... Synchronization separation circuit, 16
．． 21... Analog switch, 17... Screen synchronization circuit, 18... Modulation circuit, 19... Brightness modulation circuit, 2
0... Brightness adjustment circuit, 23... Switch control circuit,
24...Mode selection circuit. Applicant's Representative Patent Attorney Takehiko Suzue Flute Illustration 1

Claims (5)

[Claims] (1) a synchronization separation circuit that inputs a video signal and separates a vertical synchronization signal and a horizontal synchronization signal; a demodulation circuit that inputs the video signal and demodulates a subcarrier signal and an image signal;
Input the vertical and horizontal synchronization signals of the video signal obtained from the synchronization separation circuit, and input the vertical and horizontal synchronization signals from the computer, and clock the computer so that the respective vertical and horizontal synchronizations match. a screen synchronization circuit that selectively outputs an image signal obtained from the demodulation circuit and an image signal obtained from the computer; a modulation circuit that receives vertical and horizontal synchronization signals obtained from the demodulation circuit and a subcarrier signal obtained from the demodulation circuit, and outputs a video signal and a radio frequency signal; and a switching means that is controlled by the computer and controls the switching means. A superimposer characterized by comprising a control circuit. (2) When the image signal is a red, green, or blue color signal, the switching means control circuit causes the switching means to select and output the color signal from the computer when any of the color signals from the computer is valid. 2. The superimposer according to claim 1, wherein the superimposer superimposes an input image signal and an image signal from a computer under control. (3) The switching means control circuit controls the switching means so as to output an input image signal, an image signal from the computer, and an image signal obtained by superimposing both image signals. 3. The superimposer according to item 1 or 2. (4) a synchronization separation circuit that inputs a video signal and separates a vertical synchronization signal and a horizontal synchronization signal; and a demodulation circuit that inputs the video signal and demodulates a subcarrier signal and an image signal;
Input the vertical and horizontal synchronization signals of the video signal obtained from the synchronization separation circuit, and input the vertical and horizontal synchronization signals from the computer, and clock the computer so that the respective vertical and horizontal synchronizations match. a screen synchronization circuit that selectively outputs an image signal obtained from the demodulation circuit and an image signal obtained from the computer; a modulation circuit that receives vertical and horizontal synchronization signals obtained from the demodulation circuit and a subcarrier signal obtained from the demodulation circuit, and outputs a video signal and a radio frequency signal; and a switching means that is controlled by the computer and controls the switching means. 1. A superimposer comprising: a control circuit; and a prohibition circuit for prohibiting output of an input audio signal when only an image signal from the computer is selected by the switching means. (5) a synchronization separation circuit that inputs a video signal and separates a vertical synchronization signal and a horizontal synchronization signal; and a demodulation circuit that inputs the video signal and demodulates a subcarrier signal and an image signal;
Input the vertical and horizontal synchronization signals of the video signal obtained from the synchronization separation circuit, and input the vertical and horizontal synchronization signals from the computer, and clock the computer so that the respective vertical and horizontal synchronizations match. a screen synchronization circuit that selectively outputs an image signal obtained from the demodulation circuit and an image signal obtained from the computer; a modulation circuit that receives vertical and horizontal synchronization signals obtained from the demodulation circuit and a subcarrier signal obtained from the demodulation circuit, and outputs a video signal and a radio frequency signal; and a switching means that is controlled by the computer and controls the switching means. A superimposer comprising: a control circuit; and a brightness adjustment means for externally adjusting the brightness of an image signal from the computer. −